LibOverride: Minor improvement to recent liboverride API changes.

Avoid two GHash lookups when deleting an override property by its RNA
path.

@@ -217,0 +260,4 @@
+  Main *old_bmain = reuse_data->old_bmain;
+  IDRemapper *remapper = reuse_data->remapper;
+
+  for (Library *old_lib_iter = static_cast<Library *>(old_bmain->libraries.first);

@@ -217,0 +271,4 @@
+      continue;
+    }
+
+    for (Library *new_lib_iter = static_cast<Library *>(new_bmain->libraries.first);

@@ -217,0 +400,4 @@
+  wmWindowManager *old_wm = static_cast<wmWindowManager *>(old_wm_list->first);
+  wmWindowManager *new_wm = static_cast<wmWindowManager *>(new_wm_list->first);
+
+  if (old_wm != nullptr) {

@@ -217,0 +280,4 @@
+      }
+
+      BKE_id_remapper_add(remapper, &old_lib_iter->id, &new_lib_iter->id);
+    }